Fire-alarm signal-circuit.



PatentedDcLQl, I899.

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'nnumnm Ihmnmmw D L O RY filed Mar. 28, 1899.)

W R HEWITT FIRE ALARM SIGNAL CIRCUIT.

(Application SILENT TAPPE ullllmllllb llilllllllllll (No Model.)

REGISTER.

l5 FLOOR BELL NITED STATES Prion.

WILLIAM R. HEWITT, OF SAN FRANCISCO, CALIFORNIA.

FIRE-ALARM SIGNAL-CIRCUIT.

$PEGIFIGATION frming part of Letters Patent No. 636,139, dated October 31, 1899.

Application filed March 28, 1899. $erial No. 710,737- (No model.)

To all whom it may concern.-

Be it known that I, WILLIAM R. HEWITT, a citizen of the United States, residing in the city and county of San Francisco, State of California, have invented an Improvement in Fire-Alarm Signal-Circuits; and I hereby declare the following to be a full, clear, and exact description of the same.

My invention relates to such signal systems as have two independent circuits in each engine-house operated alternately from a central fire-alarm oflice. When an alarm is received at the central office, it is first repeated over one of the lines,called the main tapper-line and then sent over the other, called the main gong-line. Such an alarm would indicate the number of the station at which the fire department is due. The several companies of the fire department do not respond to every alarm, but only to such as are in the districts to which they are assigned, respectively. In order that time may be saved and by way of exercise, all companies are compelled to hitch up and get ready to start, if necessary, upon receipt of the signal in the daytime. At night, however, this is unnecessary and should be avoided.

The object of my invention is to prevent the company being aroused and called needlessly at night and to prevent a failure of sig-. nals in case the watchman fails to properly manipulate the switches of the local circuits.

In previous patents it is necessary to depend upon the watchman to set the local switches properly, and if for any reason he fails to do so the local circuit becomes inoperative, and in case of an alarm at which the company may be due there would not be a response by the company. This failure of the system is inherent and due to the possibility of the switches being set or left on the dead-points, thereby rendering the Whole system inoperative, and immediately the firealarm system loses its high efficiency, and instead of being an auxiliary of great assistance to the fire department is really a menaceto its usefulness and also to the lives and property of the community. In my invention the failure of any signals is prevented by removing all dead-points from the local circuits and by making the local switches operative at all points, thereby placing beyond the power of the Watchman to improperly manipulate the switches.

My invention, herein briefly stated, consists in an engine-house local circuit containing gongs and releasing devices so arranged as to be common in turn to two different closing-contacts and so controlled as to be normally open to one signal-circuit contact and closed to another signal-circuit contact alternately, or to be possibly closed at times to both signal-circuit contacts simultaneously, but never open to both signal-circuit contacts at the same time. To obtain this desired result, I have devised and invented a switch operated by any well-known means located at convenient points about every enginehouse.

Such an arrangement as above described provides that the signal from the tapper-line may be received at night without disturbing horses or men, While the signal over the gongline will operate the gong, unhitch thehorses, and arouse the men unless the watchman shall between the end of the signal on the tapper and beginning of the same signal over the gong-line operate the switch which shifts the main local circuit from the gong-closing contact to tapper-closing contact.

In the main tapper-circuit I place a small bell connected up as a relay to close and open a local circuitcontaining a register and another relay, the local points of which close and open the main local circuit containing the gongs and releasing devices, when said main local circuit is connected to said local points by means of the switch heretofore mentioned. In the main gong-circuit I place a small bell connected up as a relay, the local points of which close and open the main local circuit containing the gongs and releasing devices when said main local circuit is connected to said local points by means of the switch heretofore mentioned. The small bells above mentioned are sounded loud enough to be heard by the watchman awake and on duty, but not loud enough to disturb and arouse the men asleep, and are therefore called silent tappers and gongs, respectively.

The accompanying drawing is a diagrammatic view showing the arrangement of the apparatus.

ICO

The main tapper-circuit A is connected through the coil of the bell-relay B, the local points of which close and open the local circuit C, in which is placed the relay D, the local points of which close and open the circuit M M, which ends at the points E and E when not connected with the main local circuit H H through the switch G G. The main gong-circuit P is connected through the coil of the bell-relay O, the local points of which close and open the circuit N N,which ends at the points F F when not connected with the main local circuit H H through the switch G G. The main local circuit H H contains the switch G G, the first-floor gong I, the releasing devices J, the battery K, and the dormitory-gong L. The pins marked Q and B, respectively, limit the range of the switch G G.

It will be observed that the main local circuit H H by being shifted to the points E and E and F F, respectively, is common in turn to the closing contacts of the locals M M and N'N, used in connection with the main tapper and gong circuits, respectively. It will also be observed that owing to the limit-pins Q and R the switch must remain on either E and E or F and F alternately, and, further, owing to closeness of approach to each other of the points E and F and E and F at the places marked S and T, respectively, the switch G may remain on both E and F and E and F simultaneously, and from what has been previously stated it will be easily observed that the main local circuit can never be open to both signal-circuit contacts at the same time and that at night regardless of the position of the switch G G an alarm must release the horses and arouse the men if the watchman for any reason has failed to operate the switch G G, so that the whole system is really and practically inherently automatic in its action.

In actual service the following operations take place: For day service the switch G G is set on the points E and E, (indicated by the broken lines.) lVhen a signal is sent first over the circuit A, it will be recorded on the register U and at the same time release the horses and sound on the gongs I and L, thus permitting thecompany to respond immediately to the tapper-signal. The signal isimmediately repeated over the circuit P, but since the horses have already been released and gongs sounded the switch G G is allowed to remain undisturbed on the points E and E and the signal comes in as a silent call on the small bell-relay 0. At night the switch is set on the points F and F, (indicated by the full lines.) \Vhen a signal is sent first over the circuit A, it will be recorded on the register U and as a silent call on the bell-relay B. The watchman being familiar with all stations at which the company is due and having heard and counted the silent call determines that the company is not due, and immediately upon the termination of the signal over circuit a causes the switch G G to be shifted to the points E and E and there'- by transferring the main local, including the gongs and releasing devices, from the gongclosing contacts of the circuit N N, so that when the signal is repeated over the circuit P it is received as a silent call on the relaybell O, and men and horses are not disturbed. The switch is then returned to its position on F F and is then in readiness for another alarm.

In case the company should be due at a station the Watchman being alert between the first and second rounds of the signal over the tapper-circuit A will cause its switch G G to be shifted to the points E and E, thereby transferring the main local, including gongs and releasing devices, to the tapper-closing contacts of the circuit M M, and the second round of the tapper now coming in releases the horses and arouses the men. If for any reason the watchman has failed to shift the switch G G, the main local, including gongs and releasing devices, will remain on the points F and F and, controlled by the closingcontacts of the circuit N N, will be operated by the relay-bell 0 when the signal is repeated over the gong-circuit P, so that in any event the members of the company cannot fail to be aroused and the horses released.

Having thus described my invention, What I claim as new, and desire to secure by Letters Patent, is-

1. An engine-house local circuit containing gongs and releasing devices, branch circuits having difierent closing-contacts, and a switch in said local circuit so arranged as to be normally closed to diflferent closing-contacts alternately, or to the said different closing-contacts simultaneously and so arranged as not tobe open at any position to all closingcontacts simultaneously.

2. In an engine-house local circuit containing gongs and releasing devices, a switch in said local circuit so arranged as to be normally closed to diiferent closing-contacts a1;

ternately, or to the said dilferent closing-contacts simultaneously and so arranged as not to be open at any position to all of said closing-contacts simultaneously, in combination with a main tapper-circuit, a branch circuit including one set of closing-contacts, ,a relay in the local circuit of the main tapper-circuit and adapted to close said branch circuit, a second branch circuit including another set of closing-contacts, a main gong-circuit and a relay therein and adapted to close said second branch circuit substantially as herein described.

3. Ina fire-alarm signal system, a relay in the local circuit of the main tapper-line and a bell-relay in the main gong-line, in combination with an engine-house, main local containing gongs and releasing devices and having a switch so arranged as to be set alternately in circuit with the closing-contacts of said relayin the local of the main tapper-line IIO and of said bell-relay of said main gong-line, the main rapper-circuit and of said bell-relay 10 and further so arranged as to be set in cirof the main gong-circuit.

cuit simultaneously with the closing-contacts In Witness whereof I have hereunto set my of both said relay in the local circuit of the hand.

main tapper-circuit and said bell-relay of the main gong-circuit, said switch being so ar- WILLIAM HEWITT ranged as not to be in open'circuit at any Witnesses: time simultaneously with said closing-con- S. H. NOURSE, tacts of both said relay in the local circuit of JESSIE C. BRODIE. 

